Currently industrial computer has a cabinet for receiving the mainframe, keyboard, screen, hard disk. The cabinet has tracks. If it is necessary to use one device, it is pulled out by pulling a handle. Generally, the handle is protruded out from the casing surface to affect the operation of peoples passing therethrough. It is possible that the handle is damaged due to collision. Thereby the repairmen possible collide the handle as they lift their heads. Furthermore, currently, the devices in the computer cabinet are made more and more smaller and thus the distances between the handles are smaller, and thus it is possible when one handle unit is operated, the user's hand will be hurt by another handle. This defect is necessary to be improved.